Mortgage porting: take your rate with you when you move, and skip the break penalty.

Port or break — when does keeping my old rate beat just taking today’s pricing?

This is a math question, not a rule of thumb. Breaking a fixed mortgage triggers a prepayment penalty — usually the greater of three months’ interest or an interest rate differential (IRD)², which on a low-rate, long-term mortgage can run into five figures.

Porting usually avoids the break penalty. Some lenders charge it when you sell and refund it once your purchase closes inside the porting window, and porting a smaller balance can trigger a partial penalty. If your existing rate is below today’s, porting usually comes out ahead, but blend terms and closing dates can change that. We run both scenarios.

If today’s rates have fallen below yours, breaking and refinancing might win even after the penalty. We run both scenarios with your actual rate, balance, penalty, and new purchase price, and a penalty estimate so the recommendation rests on dollars, not assumptions.

What is port-and-increase, and how is the blended rate calculated?

If your next home costs more and you need a bigger mortgage, you don’t lose your old rate on the increase — you blend.

Port-and-increase keeps your existing balance at your original (often low) rate and adds the new money at today’s rate, then weaves the two into a single ‘blended rate.’ The blend is weighted by dollars: a large old balance at a low rate barely moves when you add a smaller chunk of new money, while a big increase pulls the blended rate closer to current pricing.

So if most of your mortgage is your old low-rate balance, your blended rate stays well below market. For example: $400,000 at 2.89% + $150,000 at 4.39% → (400k × 2.89% + 150k × 4.39%) ÷ 550k ≈ 3.30% blended (illustrative; lenders may also price the blend differently).

Some lenders blend-and-extend (resetting your term) and some blend-to-term (keeping it); the structure changes your payment and your next renewal date. We model the blend so you see the exact rate and payment before you commit — no surprises at signing.

How does timing work — same-day move versus selling and buying weeks apart?

Porting lives or dies on dates. The cleanest version is a simultaneous port: you sell and buy on the same day, the mortgage moves straight across, and nothing is ever broken.

But life rarely closes that neatly. Windows vary by lender: some require same-day closings, others allow roughly 30–120 days between sale and purchase. Check your mortgage terms. Close inside that window and your rate is preserved; drift past it and the port collapses into a break, penalty and all.

The window length, and whether they bridge the gap, vary widely — which is exactly why the lender you’re with matters. At porting you also re-qualify on the new property. We map your sale and purchase dates against your lender’s specific rules. If you need to buy before your sale closes, we can arrange bridge financing for the down payment; if you sell first, we make sure the purchase closes inside your lender’s porting window.

What are the catches — and why check before I list my home?

Porting isn’t automatic, and three catches trip people up. First, you re-qualify: the lender re-checks your income, credit, debt ratios, and the new home’s appraised value, and in most cases you must pass the stress test again, so if your income dropped or your debt rose since you first borrowed, the port can be denied.

Second, not every lender ports the same way; windows, blend methods, and eligible property types differ, and a few discounted ‘no-frills’ products and certain variable mortgages don’t port at all. Third, assuming wrong is expensive — discover a non-portable mortgage after you’ve firmed up an offer and you’re stuck paying the break penalty.

That’s the broker advantage. In our experience placing ports across 100+ lenders, we know which ones port cleanly (for example, on a $400,000 balance at 2.89%, three months’ interest alone is about $2,890, a penalty a clean port can avoid; an IRD penalty may be higher), we confirm your exact product before you list, and every lender and broker fee is disclosed in writing — in any of 15+ languages. Start the conversation early, before you list or offer.